1. Field of the Invention
The present invention relates to methods for making ammonium phosphate fertilizer, and more particularly to methods for making controlled-release ammonium phosphate fertilizer that releases nutrient continuously and efficiently to the soil.
2. Description of Related Arts
Ammonium phosphate is a main compound fertilizer containing nitrogen and phosphorus, two basal nutrients for plants, and takes a 58% marketing proportion of all phosphate fertilizers in the world. Ammonium phosphate is used as a base fertilizer or an additional fertilizer, and more likely to be used as a main component of a bulk blend fertilizer or compound fertilizer since the ammonium phosphate has excellent compatibility to match in harmony with other different fertilizers. Ammonium phosphate and other phosphate fertilizers such as superphosphate, triple superphosphate, nitrophosphate, and calcium magnesium phosphate have a fatal drawback in that most of the phosphate is easily fixed in soil and become too slow-released or unavailable. Therefore, the phosphorous fertilizers are not efficient for a long period of time and are not completely absorbed by plants resulting in low use efficiency of the phosphorous fertilizers as 15-20% in the growth season of plants.
The present invention has arisen to mitigate or obviate the disadvantages of the conventional phosphate fertilizers.